Add health check endpoint and refactor integration response handling

- Introduced a new public health check endpoint at `api/ping/` to verify API responsiveness.
- Refactored integration response handling to utilize a unified success and error response format across various methods in `IntegrationSettingsViewSet`, improving consistency and clarity in API responses.
- Updated URL patterns to include the new ping endpoint and adjusted imports accordingly.

frontend/src/components/common/ImageGenerationCard.tsx

@@ -138,6 +138,8 @@ export default function ImageGenerationCard({
       console.log('[ImageGenerationCard] Making request to image generation endpoint');
       console.log('[ImageGenerationCard] Request body:', requestBody);
 
+      // fetchAPI extracts data from unified format {success: true, data: {...}}
+      // So data is the extracted response payload
       const data = await fetchAPI('/v1/system/settings/integrations/image_generation/generate/', {
         method: 'POST',
         body: JSON.stringify(requestBody),
@@ -145,8 +147,10 @@ export default function ImageGenerationCard({
 
       console.log('[ImageGenerationCard] Response data:', data);
 
-      if (!data.success) {
-        throw new Error(data.error || 'Failed to generate image');
+      // fetchAPI extracts data from unified format, so data is the response payload
+      // If fetchAPI didn't throw, the request was successful
+      if (!data || typeof data !== 'object') {
+        throw new Error('Invalid response format');
       }
 
       const imageData = {

frontend/src/components/common/ValidationCard.tsx

@@ -81,38 +81,30 @@ export default function ValidationCard({
         };
       }
       
-      // Test endpoint returns Response({success: True, ...}) directly (not unified format)
-      // So fetchAPI may or may not extract it - handle both cases
+      // Test endpoint now returns unified format {success: true, data: {...}}
+      // fetchAPI extracts the data field, so data is the inner object
       const data = await fetchAPI(`/v1/system/settings/integrations/${integrationId}/test/`, {
         method: 'POST',
         body: JSON.stringify(requestBody),
       });
 
-      // Check if data has success field (direct Response format) or is extracted data
-      if (data && typeof data === 'object' && ('success' in data ? data.success : true)) {
-        // If data has success field, use it; otherwise assume success (extracted data)
-        const isSuccess = data.success !== false;
-        if (isSuccess) {
-          setTestResult({
-            success: true,
-            message: data.message || 'API connection successful!',
-            model_used: data.model_used || data.model,
-            response: data.response,
-            tokens_used: data.tokens_used,
-            total_tokens: data.total_tokens,
-            cost: data.cost,
-            full_response: data.full_response || {
-              image_url: data.image_url,
-              provider: data.provider,
-              size: data.size,
-            },
-          });
-        } else {
-          setTestResult({
-            success: false,
-            message: data.error || data.message || 'API connection failed',
-          });
-        }
+      // fetchAPI extracts data from unified format, so data is the response payload
+      if (data && typeof data === 'object') {
+        // Success response - data contains message, model_used, response, etc.
+        setTestResult({
+          success: true,
+          message: data.message || 'API connection successful!',
+          model_used: data.model_used || data.model,
+          response: data.response,
+          tokens_used: data.tokens_used,
+          total_tokens: data.total_tokens,
+          cost: data.cost,
+          full_response: data.full_response || {
+            image_url: data.image_url,
+            provider: data.provider,
+            size: data.size,
+          },
+        });
       } else {
         setTestResult({
           success: false,